1. Field of the Invention
The present invention relates generally to an apparatus for attaching a control conduit to a surgical instrument. More particularly, this invention relates to a spring-biased snap assembly for attaching a flexible control conduit to a proximal handle assembly of an endoscopic biopsy instrument.
2. Description of the Related Art
Endoscopic biopsy procedures are performed with an endoscope and an endoscopic biopsy instrument. An endoscopic biopsy instrument is a flexible medical device for insertion into a body passageway or cavity that enables a surgeon at a remote external location to remove and retrieve a tissue sample from a site internal to the patient""s body. The biopsy instrument typically includes an elongated flexible member having a tissue sampler at the distal end and a handle assembly with a manual actuator at the proximal end.
During a biopsy tissue sampling operation, a surgeon guides the endoscope to the biopsy site within the body of the patient. The biopsy instrument is then inserted through the endoscope until the tissue sampler is proximate to the tissue to be sampled. The surgeon manipulates the actuator so that a sample of tissue is torn or cut away from the biopsy site and is retained by the tissue sampler.
The handle assembly at the proximal end of the endoscopic biopsy instrument is coupled to the tissue sampler at the distal end by an elongated flexible member. Generally, the flexible member includes a control conduit or flexible coil. A control member, typically a wire, extends through and is reciprocally movable in the proximal and distal directions within the flexible coil. The control member is attached to the manual actuator at the proximal end and to the tissue sampler at the distal end of the biopsy instrument. Operation of the actuator relative to the handle causes the control member to move relative to the flexible coil and actuate the tissue sampler.
Various apparatuses have been used to attach the flexible coil to the handle assembly. Considerations include cost, ease of component manufacture, ease of assembly, expected life cycle of the biopsy instrument, operational loads, and acceptance by the operator. Surgeons would find unacceptable any attachment apparatus that permits the flexible coil to move relative to the handle during manipulation of the end effectors.
One method of attaching the coil to the handle is bonding. This may be acceptable for disposable biopsy instruments, but not for instruments that are to be autoclaved. Repeated autoclaving may degrade the bondline. Furthermore, bonding raises OSHA/SHEA concerns regarding the exposure of assembly workers to solvent fumes.
In another example, crimping a barbed crimp band onto the end of the flexible coil and then press fitting the coil with a barbed crimp band into an inner bore of the handle is relatively expensive. Additionally, press fitting the barbed crimp band into the handle may also result in unacceptably large tensile hoop stresses in the handle that may ultimately lead to cracks. Furthermore, this design creates an undesirably large gap between the outer diameter of the flexible coil and the inner bore of the handle, leaving the flexible coil unsupported within the handle and prone to bending displacements. In instruments that incorporate an anti-kink tube for supporting the control wire at its proximal end, the bending of the flexible coil may interfere with the sliding of the anti-kink tube within the flexible coil during actuation of the actuator. This interference may subject the operator to a disagreeable grating feel and noise.
Objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention includes an assembly connecting a flexible coil to a handle member of a endoscopic instrument. The assembly includes a handle member, a hollow nose member and a biasing element. The handle member has an inner bore. The hollow nose member has a shank configured for insertion into the inner bore and for receiving the flexible coil. The biasing element is located within the inner bore and is for biasing the flexible coil relative to the handle member.
This assembly may include a retaining element affixed to a proximal end of the flexible coil and configured for retention between the handle member and the nose member. The handle member may include one of a keyway or a projection configured for insertion into a keyway and the nose member may include the other of the keyway or the projection. The biasing element may be formed as an integral portion of the nose member, formed as an element separate from the nose member, or formed as an integral portion of the flexible coil.
In another aspect, the invention comprises an assembly for connecting a flexible coil to a handle of an endoscopic instrument, wherein the assembly includes a handle member and a hollow nose member. The handle member has an inner bore and one of a keyway or a projection configured for insertion into a keyway; the hollow nose member has a shank configured for insertion into the inner bore and for receiving the flexible coil. The nose member includes the other of the keyway or the projection.
The shank of this assembly may include a slot extending distally from the proximal end of the shank and thereby forming two resilient arms on the shank. This assembly may further include a retaining element affixed to a proximal end of the flexible coil and configured for retention between the arms of the shank. The retaining element may be integrally formed from the flexible coil.
In a further aspect, the invention comprises an endoscopic instrument having an end effector assembly, a flexible member and a handle assembly. The end effector assembly is located at the distal end of the endoscopic instrument. The flexible member is connected to and extends from the end effector assembly. The handle assembly includes a handle member having an inner bore, a hollow nose member having a shank configured for insertion into the inner bore, and a biasing element within the inner bore for biasing the flexible member relative to the handle member, wherein the flexible member is inserted into the hollow nose member and connected to the handle assembly.
The handle member of this instrument may include one of a keyway or a projection configured for insertion into a keyway, and the nose member may include the other of the keyway or the projection. The flexible member may have a retaining element affixed to an end portion opposite the end effector assembly, the retaining element configured for retention between the handle member and the nose member. The biasing element may be an integrally formed portion of the nose member; formed as an element separate from the nose member; or an integrally formed portion of the flexible member. The flexible member of this instrument may be coupled to the handle assembly by inserting the flexible member through the biasing element and through the hollow nose member thereby locating the biasing element between the nose member and the retaining element, inserting the hollow nose member, biasing element and retaining element into the inner bore of the handle member, and inserting the projections into the keyways.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.